Metal alloy for use in manufacturing electrical contacts



Patented Oct. 22, 1929 UNITED STATES PATENT OFFICE HARDY M. FREDBIKSEN, OF SEATTLE, WASHINGTON No Drawing. Application filed May 31,

This invention relates to metal alloys and it has for its object to provide an alloy having marked advantages for use in the manufacture of electrical contacts, though it is not limited to such use. It is a well known fact that at the present time it is necessary to employ high grade and expensive metals as contact points in electrical apparatus, owing to the extremely severe. usage to which said points are subjected. In order to resist the burning, pitting and the building up of projections or teats or nodules upon the points, materials as expensive as platinum are commonly employed.

It is the primary object of my invention to provide an alloy which will be relatively cheap, will possess high conductivity and will resist burning, pitting and building up far more effectively than is possible with any metal, irrespective of cost, at present known to the electrical art.

I secure one of the elements of my alloy from the cathode of an electrolytic refining apparatus.

The known and commonly used electroly tic copper refining apparatus comprises an anode and a cathode which are immersed in a suitable electrolyte, such, for example, as a solution of copper sulphate and an 8 per cent solution of sulphuric acid. The current travels from the anode to the cathode carrying with it the particles of copper. Any gold and silver present fall to the bottom of the tank and are'called anode mud.

Should the cathode be uneven on the surface, this point will grow or sprout a copper nodule. This nodule may have a number of 4 branches, growing much after the manner of a piece of coral. The presence of these .40 nodules in electrolytic refining apparatus is undesirable and, their growth is avoided as much as possible. However, since these nodules are conductors of electricity, it is clear that as soon as one starts to grow, the

increased cathode area thereby provided will cause a comparatively rapid building up of l the nodule which must be removed in order to prevent it from spanning the space between the anode and the cathode. nodules, constituting an undesirable by- These 1927/ Serial No. 195,290.

product of electrolytic copper refining processes, I have discovered to possess highly advantageous properties in the manufacture of electrical contacts. I am unable to state the exact reason, but tests have shown that this material possesses characteristics different from the copper delivered by the refining apparatus and resulting, when the nodule material is mixed with certain other metals, in the production of an alloy adapted for use in the manufacture of electrical contacts of a high degree of excellence. The contacts so produced will possess a high degree of conductivity, will withstand the hi h temperatures resulting from the arcing o the current in electrical apparatus when contacts are broken and will be markedly free of pitting, building up or other unevenness of surface, such as commonly found in the use of known materials.

While the invention is not limited to the use of particular percentages or temperatures,

one embodiment of my invention may be produced by mixing per cent of pure silver with 20 per cent of the nodule material above described. Proper combining of the metals may be brought about by fusing them at comparatively high heat.

7 While the use of silver as the companion metal is preferred, it is to be understood that the invention includes the use of the baser and cheaper' metals, if it be desired to produce a different grade of contact material. Thus I may use nickel, tin or any other suitable metal, in combination with the nodule material.

While silver alone will readily amalgamate with mercury, the alloy of the present invention is found'to be markedly resistant to amalgamation with mercury. For that reason electrical contacts made of this alloy are of greatvalue for use in mercury switches and like apparatus employing mercury.

It is to be understood that the invention is not limited to particular details of percentage, temperature, etc., but that it includes within its purview any changes which are fairly within either the terms or the spirit of the appended'claims.

Having described my invention what I claim is:

1. A metal alloy comprising the nodule material left from electrolytic copper refining and silver in substantially the proportions of er centof silver and 20 per cent of the nodu e material. 7

2. The herein described alloy consisting of substantially 20% of nodule material and 80 per cent of silver united into an alloy at a temperature materially in excess of the melting point of either of said materials.

3. An electrical contact material of high conductivity, and highly resistant to burning or pitting, which has, as an essential element thereof, the residual nodule material left from electrolytic copper refining.

4. An electrical contact material of high conductivity, and highly resistant to burning or itting, which comprises the nodule material left from electrolytic copper refining and silver.

5. An electrical contact material of high conductivityflmd highly resistant to burning or pitting, which comprises the residual nodule material left from electrolytic cop per refining, and another metal capable of amalgamation therewith.

6. The hereindescribed alloy,- consisting of the nodule material left from electrolytic copper refining and silver, wherein the silver is in predominating amount with respect to the said nodule material.

In testimony whereof he afiixes his signature.

HARDY M. FREDRIKSEN. 

